Plasma 5-hydroxytryptamine (5-HT) in migraine during an attack-free period

Objective. - We measured the plasma 5-HT, 5-hydroxytryptophan (5-HTP), and tryptophan levels in controls, migraine patients with aura (MWA), and migraine patients without aura (MWoA) during an attack-free period. Background. - Serotonin (5-hydroxytryptamine, 5-HT) has been implicated in the pathophysiology of migraine. The precise relationship between 5-HT and migraine, however, remains unclear. Methods. - Blood samples in controls, MWA, and MWoA patients during an attack-free period were collected from brachial arteries and analyzed using HPLC. Results. - The plasma tryptophan and 5-HTP levels were not significantly different between the controls and migraine patients (either MWA or MWoA). However, the plasma 5-HT level in the MWA patients was significantly lower than that in the controls and MWoA patients. Conclusions. - The present data suggest that reduced levels of 5-HT in MWA may result from either a dysfunction in the enzymes involved in serotonin biosynthesis or a dysfunction in 5-HT release or uptake from platelets and lymphocytes. These findings indicate the existence of a serotonin metabolism dysfunction in MWA patients that may differ from the state of serotonin metabolism in MWoA patients.